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91 lines
3.0 KiB
ArmAsm
91 lines
3.0 KiB
ArmAsm
/* lround function. PowerPC32 version.
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Copyright (C) 2004-2013 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<http://www.gnu.org/licenses/>. */
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#include <sysdep.h>
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#include <math_ldbl_opt.h>
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.section .rodata.cst4,"aM",@progbits,4
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.align 2
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.LC0: /* 0.5 */
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.long 0x3f000000
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.section ".text"
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/* long [r3] lround (float x [fp1])
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IEEE 1003.1 lround function. IEEE specifies "round to the nearest
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integer value, rounding halfway cases away from zero, regardless of
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the current rounding mode." However PowerPC Architecture defines
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"round to Nearest" as "Choose the best approximation. In case of a
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tie, choose the one that is even (least significant bit o).".
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So we can't use the PowerPC "round to Nearest" mode. Instead we set
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"round toward Zero" mode and round by adding +-0.5 before rounding
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to the integer value. It is necessary to detect when x is
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(+-)0x1.fffffffffffffp-2 because adding +-0.5 in this case will
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cause an erroneous shift, carry and round. We simply return 0 if
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0.5 > x > -0.5. */
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ENTRY (__lround)
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stwu r1,-16(r1)
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cfi_adjust_cfa_offset (16)
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#ifdef SHARED
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mflr r11
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cfi_register(lr,r11)
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SETUP_GOT_ACCESS(r9,got_label)
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addis r9,r9,.LC0-got_label@ha
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lfs fp10,.LC0-got_label@l(r9)
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mtlr r11
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cfi_same_value (lr)
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#else
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lis r9,.LC0@ha
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lfs fp10,.LC0@l(r9)
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#endif
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fabs fp2, fp1 /* Get the absolute value of x. */
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fsub fp12,fp10,fp10 /* Compute 0.0. */
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fcmpu cr6, fp2, fp10 /* if |x| < 0.5 */
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fcmpu cr7, fp1, fp12 /* x is negative? x < 0.0 */
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blt- cr6,.Lretzero
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fadd fp3,fp2,fp10 /* |x|+=0.5 bias to prepare to round. */
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bge cr7,.Lconvert /* x is positive so don't negate x. */
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fnabs fp3,fp3 /* -(|x|+=0.5) */
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.Lconvert:
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fctiwz fp4,fp3 /* Convert to Integer word lround toward 0. */
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stfd fp4,8(r1)
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nop /* Ensure the following load is in a different dispatch */
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nop /* group to avoid pipe stall on POWER4&5. */
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nop
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lwz r3,12(r1) /* Load return as integer. */
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.Lout:
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addi r1,r1,16
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blr
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.Lretzero: /* when 0.5 > x > -0.5 */
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li r3,0 /* return 0. */
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b .Lout
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END (__lround)
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weak_alias (__lround, lround)
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strong_alias (__lround, __lroundf)
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weak_alias (__lround, lroundf)
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#ifdef NO_LONG_DOUBLE
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weak_alias (__lround, lroundl)
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strong_alias (__lround, __lroundl)
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#endif
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#if LONG_DOUBLE_COMPAT(libm, GLIBC_2_1)
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compat_symbol (libm, __lround, lroundl, GLIBC_2_1)
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#endif
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